1. Field
Apparatuses and methods consistent with the exemplary embodiments relate to a liquid crystal display (LCD) device, and more particularly, to a backlight unit employing a quantum dot (QD) bar and a light emitting diode (LED) as a light source, a manufacturing method thereof, and an LCD device having the same.
2. Description of the Related Art
A backlight unit for an LCD device includes light emitting diodes 10 arranged along a lateral side of a light guide plate 20 as shown in FIG. 18. Light emitted from the LED 10 enters the lateral sides of the light guide plate 20, propagates to the center of the light guide plate 20 by total reflection, and exits the light guide plate 20 through a front patterned surface, thereby materializing a surface light source.
Usually, white LEDs emitting monochromatic light have been used as the LEDs 10 arranged along the lateral sides of the backlight unit. The white LEDs generally emit white light by using a Blue-chip along with green and red phosphors.
The LEDs 10 used in the related art backlight unit employs a single LED package that emits one color, and therefore their color reproduction is just 75% of a national television system committee (NTSC) area. Also, the color reproduction, efficiency and white coordinate of a panel is susceptible to matching between a peak wavelength of three colors, red, green and blue (R, G, B), of the white LED and a peak wavelength of a color filter for the liquid crystal of the LCD device.
To make up for deterioration in the color reproduction of the white LED used in the related art backlight unit, there has been proposed technology of using a blue LED 10 instead of the white LED and a quantum dot (QB) bar 30 as a light source of the backlight unit, disclosed in Korean Patent Publications No. 10-2011-0068110 and No. 10-2011-0012246.
As shown in FIG. 19, the QD bar 30 is adhered between the blue LED 10 and the light guide plate 20 by a transparent optical resin layer or an adhesive layer 40, 50. However, it is very inconvenient to use the optical resin layer or the adhesive layer 40, 50 in the adhesion for the QD bar 30, and thus productivity decreases. Further, the optical resin layer or the adhesive may distort the light emitted from the LED and the QD bar.
Also, heat generated by the LED is transferred to the light guide plate 20 via the optical resin layer or the adhesive layer, and therefore the light guide plate 20 is twisted, thereby having an effect on the adhered QD bar 30 which damages the QD bar 30.